CSICS 2013 Monterey, California

A DC-100 GHz Bandwidth and 20.5 dB Gain Limiting Amplifier in 0.25μm InP DHBT

Technology

Saeid Daneshgar, Prof. Mark Rodwell (UCSB)Zach Griffith (Teledyne Scientific Company)

CSICS 2013 Monterey, California

Outline

Slide 2

• Application and Motivation of the work

• TSC 250nm HBT process overview

• Block diagram & schematic of the circuit

• Layout & EM modeling

• Measurement results and comparison table

CSICS 2013 Monterey, California

Motivation - I

Slide 3

50 GSample/sec Sample & Hold circuit

CSICS 2013 Monterey, California

Motivation - II

Slide 4

50 GHz clock circuit

CSICS 2013 Monterey, California

Applications - I

Slide 5

• High speed optoelectronic signal conversion requires broadband receivers

• Limiting amplifiers are the key components in these receivers in order to:

Provide a low input sensitivity and sufficient gain to achieve saturated output levels from small-signal inputs which enables reliable decision making

Provide a wide bandwidth to achieve short rise and fall times in order to provide an output signal with minimum distortion

CSICS 2013 Monterey, California

TSC 250nm InP HBT process

Slide 6

• Four metal interconnect stack• Peak bandwidth of ft=400 GHz & fmax = 700 GHz• MIM caps of 0.3 fF/μm2

• Thin-film resistors 50 Ω/square

• Plot courtesy Zach Griffith, UCSB 250nm InP HBT, 2007

CSICS 2013 Monterey, California

Modified Cherry-Hooper stage [1-3]

Slide 7

[1] Y. M. Greshishchev et al., “A 60-dB gain, 55-dB dynamic range, 10-Gb/s broad-band SiGe HBT limiting amplifier,” IEEE JSSC,

vol.34, no.12, pp. 1914-1920, Dec. 1999.

[2] K. Ohhata et al., “Design of a 32.7-GHz bandwidth AGC amplifier IC with wide dynamic range implemented in SiGe HBT,”

IEEE JSSC, vol.34, no.9, pp. 1290-1297, Sep. 1999

[3] C. D. Holdenried et al., “Analysis and design of HBT Cherry-Hooper amplifiers with emitter-follower feedback for optical

communications,” IEEE JSSC, vol.39, no.11, pp. 1959-1967, Nov. 2004.

Large signal behavior:

Conventional C-H amp. gain ≈ gm1-2 RF

Modified C-H amp. provides gain enhancement

by a factor of while 0 < < 2.5

CSICS 2013 Monterey, California

Block Diagram

Slide 8

Single-ended gain and BW measurements have be chosen due to

unavailability of 4-port s-param measurement for frequencies > 67 GHz

→ ~6dB gain has been added to get the differential equivalent

CSICS 2013 Monterey, California

Schematic

Slide 9

R1 =30 Ω

R2 =50 Ω

RF =40 Ω

Q1-8 =3x0.25 μm

CSICS 2013 Monterey, California

Compact layout

Slide 10

425 µm

500 µm

140 µm

100 µm

CSICS 2013 Monterey, California

Symmetric layout

Slide 11

CSICS 2013 Monterey, California

EM Simulation

Slide 12

54 port data item

Whole chip has been modeled using ADS momentum EM simulator

CSICS 2013 Monterey, California

S-parameter measurement results - I

Slide 13

Single-ended insertion lossSingle-ended input and output

return loss

• S21=14.5 dB , 3dB BW = 100 GHz• S21 gain ripple < ±0.5 dB

• S11< -20 dB , S22< -15 dB

CSICS 2013 Monterey, California

S-parameter measurement results - II

Slide 14

Rollet Stability factor Group Delay

Group delay ≈ 9 psecGroup delay variation = 11 psec

CSICS 2013 Monterey, California

Eye diagrams @ 30 Gb/s

Slide 15

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CSICS 2013 Monterey, California

Eye diagrams @ 40 Gb/s

Slide 16

Smal

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CSICS 2013 Monterey, California

Comparison table

Slide 17

CSICS 2013 Monterey, California Slide 18

Thank you for your listening